Universal mobile telecommunication systems (UMTS) and wireless local area network (WLAN) technologies are widely used in current wireless communication systems. Since the coverage areas of UMTS and WLANs are often overlapped, an inter-networking of UMTS and WLAN networks has been developed. An inter-working WLAN (I-WLAN) is a WLAN with a connection to a UMTS core network so that the services provided by the UMTS may be forwarded through the I-WLAN.
Currently, the network selection of an I-WLAN requires that a WTRU scan for available WLAN systems using their service set identifiers (SSIDs). The scanning of SSIDs can be done either passively or actively. In passive scanning, the WTRU observes information broadcast from each WLAN and determines its availability according to the signal strength. In active scanning, the WTRU transmits a probe request containing a specific WLAN SSID and waits for confirmation of the availability from that WLAN.
These techniques, however, do not provide any indication of the WLAN (SSID) that provides access to UMTS based services. Several solutions have been devised including broadcasting of the home public land mobile network (PLMN) identification over the WLAN broadcast channel. However, such techniques are vulnerable to spoofing, (disruptive WLAN operators may broadcast the same SSIDs and PLMN ID), since WLAN SSIDs are not unique.
Therefore, the selection of a UMTS based I-WLAN for connecting to UMTS based services can be a problem due to the large number of WLAN networks (SSIDs) that the WTRU must choose from and the ease of using similar SSIDs by disruptive operators in order to direct the traffic toward their networks. Accordingly, there is a need for a method and system for providing an indication of WLANs (SSIDs) that provide access to UMTS based services.